The present invention relates generally to a ball-check valve for a pump, and more particularly to a valve for use in the vertical piping of a sanitary diaphragm pump.
Diaphragm pumps are well known and are often used in the food industry where the sanitary condition of the pump and its valves are a prime consideration. A ball-check valve used in a sanitary pump requires inspection at frequent intervals of the valve seat, the ball, and other internal surfaces to check for entrapped food particles that can cause buildup of bacteria. The porosity of stainless steel and the surface roughness of welds are problems in such an application.
Known ball-check valves such as disclosed in the Hallstrom Jr. U.S. Pat. No. 2,934,024 dated Apr. 26, 1980, include a removable ball and valve seat, but is not readily inspected. Other valves, such as the Wilden Model M-8 "Foodmaster" pump, include a removable elastomer valve seat, an elastomer ball, and a ball valve cage. These features facilitate inspection and cleaning of the valve, but the valve seat, because of constant friction in use, requires frequent replacement. Moreover, the valve cage is larger in size, expensive to manufacture, reduces the size of particles which can pass through the valve, and increases the time necessary for inspection and cleaning.
Other known valves such as the Depa DL-40SL replace the removable valve seat with an integral seat and replace the valve cage with a solid bar ball stop welded into the valve housing from the outside, since welding is unacceptable for sanitary application on the inside because of the extreme difficulty to weld, grind and polish. However, this lack of unitary structure on the inside results in bacterial buildup. In addition, this design does not permit a visual inspection of the inside passages of the valve.
It is accordingly an object of the present invention to obviate the above described deficiencies and to provide a novel ball-check valve for use in a sanitary pump or other application.
It is another object of the present invention to provide a novel ball-check valve which is less expensive to produce, self-cleaning in design, and easily inspected.
It is still another object of the present invention to provide a novel ball-check valve structure with an integral housing and valve seat and easily removable ball stop.
It is yet another object of the present invention to provide a novel ball-check valve in which all internal surfaces may be visually inspected when looking inward from the outlet end of the valve.
It is a further object of the present invention to provide an anti-stall ball-check valve for a low pressure pump.
Yet a further object of the present invention is to provide a novel ball-check valve in which elastomer-to-elastomer contact is avoided.
Yet another object of the present invention is to provide a novel ball-check valve which does not require welding.
Yet a further object of the present invention is to provide a novel ball-check valve which has a valve seat unitary with the valve housing so that the difficulty in valve seat removal and bacterial build-up can be avoided.
These and many other objects and advantages will be readily apparent to one skilled in the art to which the invention pertains from a perusal of the claims and the following detailed description of the preferred embodiments when read in conjunction with the appended drawings.